DUBLIN, Ohio, June 2 (Reuters) - Ice-cool Matt Kuchar held off a late challenge from fellow American Kevin Chappell to clinch the Memorial Tournament by two shots on Sunday and become the PGA Tour's second multiple winner this year.

Leading by two going into the final round at Muirfield Village Golf Club, the 34-year-old Kuchar was never caught as he fired a four-under-par 68 in the high-profile event hosted by Jack Nicklaus.

Kuchar birdied all four of the par-fives on the heavily tree-lined layout to remain in control and rubber-stamped his win by sinking a 20-foot birdie putt at the par-four last for a 12-under total of 276.

Chappell, seeking his first PGA Tour victory, birdied four of the last six holes for a bogey-free 68 and outright second place while five-times champion Tiger Woods ended a forgettable week with a 72, finishing a distant 20 strokes off the pace.

American Kyle Stanley, who briefly cut Kuchar's lead to one with a sizzling run of four birdies in five holes on the front nine, faded to a 71 for third place at seven under.

Kuchar, however, reigned supreme on perhaps the easiest day for scoring in easing winds after a challenging week at Muirfield Village where strong gusts and lightning-fast greens had posed all sorts of problems for the players.

Having clinched one of the biggest victories of his career at the WGC-Accenture Match Play Championship in February, Kuchar emulated Woods as a multiple champion this season and pocketing the winner's cheque for $1.116 million.

"It's a real honour to win this tournament," Kuchar said to 18-times major champion Nicklaus as he was greeted with a handshake by his long-time idol after walking off the 18th green.

"This is such an amazing feeling," Kuchar, who will rise to a career-high fourth in the world rankings on Monday, later told CBS Sports. "This never gets old."

FAST START

Kuchar made a fast start to the final round, sinking a 14-foot birdie putt at the par-four first to move three strokes clear.

However, he succumbed to the lurking danger on the slick greens when he recorded a three-putt bogey at the par-three fourth, missing a three-footer to slip back to eight under.

Scott Stallings, who had reeled off five consecutive birdies from the fourth, briefly closed to within a stroke of the lead when he sank a seven-foot birdie putt at the par-four 10th.

Kuchar countered with two-putt birdies at the par-five fifth and the par-five seventh to regain a three-shot cushion before reaching the turn in two-under 34.

At that point, he was one ahead of Stanley, who had birdied the fifth, sixth, eighth and ninth.

Kuchar benefited from a two-shot swing at the par-five 11th where he rolled in a 14-footer for birdie to lead by three after Stanley, who ended up under the lip of a fairway bunker off the tee, bogeyed the hole.

With none of his closest challengers applying any sustained pressure, Kuchar increased his advantage to four with another two-putt birdie at the par-five 15th.

Kuchar bogeyed the par-three 16th after his tee shot ran through the fringe into tangly grass from where his chip ended 14 feet beyond the hole and his lead was cut to two when Chappell sank a 20-footer to birdie the 17th.

Though Chappell struck a superb approach to just two feet at the last to set up his fourth birdie of the round, Kuchar matched him when he stunningly sank his attempt from 20 feet.

Woods, who began the day 16 strokes off the pace after struggling with his putting over the first three rounds, came badly unstuck with a triple-bogey at the par-three 12th, his third hole of the day.

However, five birdies in his last 13 holes gave himself something to build on as he now prepares for the second major of the year, the June 13-16 U.S. Open at Merion

"It wasn't like it was that far off today," Woods said after finishing at wight over 296. "It was just one hole that cost me obviously a few shots.

"It happens. It happens to us all. I go home next week and practise. It's just one of those weeks. It happens. This week I obviously didn't putt well. I had some funky stances." (Reporting by Mark Lamport-Stokes; Editing by Julian Linden)